Kline Fogleman 3 (KFM3) Polystyrene Foam wing for UDB2 / Matrixpilot UAV


Hi. I have finished the first prototype of the lightweight KFM3 wing for my UDB2 / Matrixpilot UAV. The wing is made entirely out of Polystyrene. The benfits of this wing are: wide AOA range, wider stable CG range since lift is produced farther back on the wing surface, no aileron reflex needed so lower aileron reflex drag. I will add vinglets to reduce wingtip vortexes and drag due to vortex leakage out from the rear KFM surfaces.


This design should also give a low wingloading for autopiloted photo missions in low speed.


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T3
Comment by Jared S on July 15, 2010 at 7:54pm
Does that wing shape have a name? Any more info on it? White papers?

Moderator
Comment by Gary Mortimer on July 16, 2010 at 3:31am
There does not seem to be any sweep on that, is it a plank???
Comment by UFO-MAN on July 16, 2010 at 3:41am
This is a Kline Fogleman type 3 wing. http://en.wikipedia.org/wiki/Kline_Fogleman_airfoil

You can see several NASA publications about tests that have been done and a more popular scientific coverage here: http://www.youtube.com/watch?v=6H-s7yuJcwk&feature=player_embed...

More info and tests: http://www.rcpowers.com/forum/blog.php?b=20/

Patents:
http://www.google.com/patents?vid=3706430
http://www.google.com/patents?vid=4046338

The basic idea is that a vortex is generated behind the steps and that this vortex causes the airflow to not de-attach from the surface of the vortex. This causes less drag. The wing also is claimed to have a wider CG range, a wider lift generating AOA range and several other benefits. Some authors claim it generates more drag, but that is disputed from several other sources. The wing has not been used extensively in commercial aicraft, but many RC aircraft builders have tested this wing. I intend to use it in an UAV project.
Comment by Chris McNair on July 16, 2010 at 8:43pm
We did a lot of work with this about 5 years ago. It does work and well. Don’t you think the step is a bit large or did you base that off something your read? Nice work! Looking forward to the results.

Chris
Comment by UFO-MAN on March 19, 2011 at 4:34am

Hi Chris. The step may probably be too large. However I think I recall that I based the step measurements on the wikipedia article about kfm. Something about percentages of the height, if I recall correctly.  I haven't flown it yet. However I have now attached a carbon fiber dual tail-boom setup with large tail and dual rudder control surfaces for controlling large weight shifts in towing operations. Need to make fuselage, add motor etc and I am not sure when (if) it will be finished.

 

Do you have some info on the tests you did?

 

ufo_man

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